Serverless AWS Translation using Node.js Typescript

This project has been generated using the aws-nodejs-typescript template from the Serverless framework.

For detailed instructions, please refer to the documentation.

Installation/deployment instructions

Depending on your preferred package manager, follow the instructions below to deploy your project.

Requirements: NodeJS lts/fermium (v.14.15.0). If you're using nvm, run nvm use to ensure you're using the same Node version in local and in your lambda's runtime.

Using Yarn

• Run yarn to install the project dependencies
• Run yarn sls deploy to deploy this stack to AWS

Test your service

This template contains a single lambda function triggered by an HTTP request made on the provisioned API Gateway REST API /translate route with POST method. The request body must be provided as application/json. The body structure is tested by API Gateway against src/functions/translate/schema.ts JSON-Schema definition: it must contain the name property.

• sending a POST request to /translate with a payload not containing a string property named text and language will result in API Gateway returning a 400 HTTP error code
• sending a POST request to /translate with a payload containing a string property named text and language code like fr, de, will result in API Gateway returning a 200 HTTP status code with a desired response containing the translated text.

⚠️ As is, this template, once deployed, opens a public endpoint within your AWS account resources. Anybody with the URL can actively execute the API Gateway endpoint and the corresponding lambda. You should protect this endpoint with the authentication method of your choice.

Locally

In order to test the translate function locally, run the following command:

• npx sls invoke local -f translate --path src/functions/translate/mock.json if you're using NPM
• yarn sls invoke local -f translate --path src/functions/translate/mock.json if you're using Yarn

Check the sls invoke local command documentation for more information.

Remotely

Copy and replace your url - found in Serverless deploy command output - and name parameter in the following curl command in your terminal or in Postman to test your newly deployed application.

curl --location --request POST 'https://myApiEndpoint/dev/translate' \
--header 'Content-Type: application/json' \
--data-raw '{
    "text": "I love you",
    "language": "de"
}'

Template features

Project structure

The project code base is mainly located within the src folder. This folder is divided in:

• functions - containing code base and configuration for your lambda functions
• libs - containing shared code base between your lambdas

.
├── src
│   ├── functions               # Lambda configuration and source code folder
│   │   ├── translate
│   │   │   ├── handler.ts      # `translate` lambda source code
│   │   │   ├── index.ts        # `translate` lambda Serverless configuration
│   │   │   ├── mock.json       # `translate` lambda input parameter, if any, for local invocation
│   │   │   └── schema.ts       # `translate` lambda input event JSON-Schema
│   │   │
│   │   └── index.ts            # Import/export of all lambda configurations
│   │
│   └── libs                    # Lambda shared code
│       └── apiGateway.ts       # API Gateway specific helpers
│       └── handlerResolver.ts  # Sharable library for resolving lambda handlers
│       └── lambda.ts           # Lambda middleware
│
├── package.json
├── serverless.ts               # Serverless service file
├── tsconfig.json               # Typescript compiler configuration
├── tsconfig.paths.json         # Typescript paths
└── webpack.config.js           # Webpack configuration

3rd party libraries

• json-schema-to-ts - uses JSON-Schema definitions used by API Gateway for HTTP request validation to statically generate TypeScript types in your lambda's handler code base
• middy - middleware engine for Node.Js lambda. This template uses http-json-body-parser to convert API Gateway event.body property, originally passed as a stringified JSON, to its corresponding parsed object
• @serverless/typescript - provides up-to-date TypeScript definitions for your serverless.ts service file
• @aws-sdk/client-translate - provides AWS SDK for JavaScript Translate Client for Node.js, Browser and React Native.